1. Field of the Invention
This invention relates to a meter module assembly that facilitates electric wiring and mounting of electric instruments in the instrument panel and its periphery of an automobile.
2. Description of the Prior Art
A great number of electric equipment are disposed in and around the instrument panel mounted in a vehicle body. Therefore, the control units monitoring and controlling the electric equipment, meters, indicator lamps, switches, and the like are also concentrated therein. Consequently, the number of wires that constitute instrument panel wiring harnesses becomes enormous, making the harnesses enlarged and heavy and causing the wiring of the harnesses complicated, resulting in much labor and time required in installation. The maintenance is also made difficult.
For the purpose of easing such an undesirable situation, it is proposed in Japanese Patent Specification Publication No. Sho 57-38457 that, to simplify the wiring of wiring harnesses and to prevent their enlargement, a plurality of electric junction boxes, in which concentrate branch connections of wiring harnesses and carry a number of circuit-protecting fuses and control relays, are dispersively arranged at suitable places in a vehicle.
Further, in Japanese Patent Application Laying-open No. Hei 4-266537, a circuit structure is proposed which comprises, as shown in FIG. 12, switches/instruments (not shown) implemented in a cluster b of an instrument panel a; a flexible printed circuit board c glued to the rear surface of the cluster b for forming electric circuits for the switches/instruments; and circuit boards e with dispersively arranged electric function parts d for storage, operation and the like needed for the electronic control of the switches/instruments, the circuit boards e being connected to the terminals of the printed circuit board e.
It is to be noted, however, that when the internal circuits of the meter panel take the place of a part of the branch circuits of the wiring harness or of the electric junction box, insofar as the control units for the electric equipment are dispersively arranged, there is a limit to simplifying the wiring harnesses, which making it difficult to cope with accelerative electronization foreseen in view of pursuit of safety and comfortableness in vehicles.
Further, although the dispersively arrangement of the electric circuits(flexible printed circuit board) for the switches/instruments and the electronic control substrates directly on the cluster rear surface is advantageous in concentrating their control circuit units on the rear surface, it involves the following disadvantages that it is technically difficult to adapt them to the irregularities on the rear surface. Further, for each type and grade of vehicles and each partial change in the specification, the design and production process must be changed, resulting in an increase in cost in case of multi-kind and small-quantity production.
Accordingly, the same applicant as the one of the present invention has made the application of Japanese Patent Application No. Hei 5-333752 in respect of an invention which facilitates electric wiring and installation of electric instruments in the instrument panel.
In the specification of the Application No. Hei 5-333752, as shown in FIG. 13, there is provided a meter module assembly J which comprises: a combination meter panel f implemented with meters/indicating lamps and a drive circuit therefore; an electric junction box g integrating functional circuits to distribute and control power sources and input/output signals for the vehicle-mounted electric equipment including the meters/indicating lamps; a switch unit h integrating switches for vehicle-mounted electric equipment; and wherein the combination meter panel, the electric junction box, and the switch unit are mounted and integrally united in the meter module assembly.
However, regarding to the arrangement in the meter module assembly J, as shown in FIGS. 14 and 15, the electric junction box g must project from the rear surface of a combination meter panel f, thereby occupying a large space in the instrument panel. As a result, there have been a drawback that the mounting of other equipment parts and the wiring of highly integrated electrical wires are difficult.